This invention relates to footwear, and more particularly to a new and improved spring heel sole construction that is especially advantageous in running shoes.
Running shoes today deal primarily with shock absorption. In the manufacture of shoes, many arrangements have been used or suggested to dissipate the energy at heel strike in the gait cycle. The energy generated by the foot striking the ground is dissipated either through the midsole of the shoe into the foot and leg of the athlete or as heat by conventional resilient cushioning materials after energy absorption. Although shock is absorbed, the runner loses a significant portion of his or her kinetic energy every time his or her foot strikes the ground.
Accordingly, it is an object of the present invention to provide a shoe construction which transiently stores and returns energy to the runner, as well as provide shock absorption. By the shoe returning energy to the wearer, the wearer will expend less energy during his or her activity. Improved shock absorption is provided due to the dynamic nature of the shoe constrution which causes it to adjust according to the load imposed upon it.